逗号在jQuery中分隔列表

Question

我正在尝试从表单上检查的内容创建逗号分隔列表.

var $StateIDs = $(':checked');
var StateIDs = '';
for (i=0, j = $StateIDs.length; i < j; i++) {
    StateIDs += $StateIDs[i].val();
    if (i == j) break;
    StateIDs += ',';
}

可能有一个可以做到这一点的单线程,或单个功能.

Answer 1

map()将成为你的朋友.

var StateIDs = $(':checked').map(function() { 
    return this.value; 
}).get().join(',');

StateID将是逗号分隔的字符串.

一步一步 - 发生了什么？

$(':checked')
// Returns jQuery array-like object of all checked inputs in the document
// Output: [DOMElement, DOMElement]

$(':checked').map(fn);
// Transforms each DOMElement based on the mapping function provided above
// Output: ["CA", "VA"]  (still a jQuery array-like object)

$(':checked').map(fn).get();
// Retrieve the native Array object from within the jQuery object
// Output: ["CA", "VA"]

$(':checked').map(fn).get().join(',');
// .join() will concactenate each string in the array using ','
// Output: "CA,VA"